It is conventional practice in attaching an article to a supporting surface, such as, for example, attaching a bracket to a wall, to first drill a pilot hole in the supporting surface and then pass a screw through the article to be attached and thread the screw into the pilot hole.
Several steps are required to accomplish this when using a conventional electric drill to power a conventional drill bit and a conventional screwdriver. First, the right size drill bit must be selected and mounted in the chuck of the electric drill. Then the electric drill must be activated to drill the pilot hole in the supporting surface. The electric drill is then deactivated and the drill bit is removed and replaced by a screwdriver in the chuck of the electric drill. Finally, the electric drill is reactivated to fasten the article to the supporting surface by passing a screw through the article and threading the screw into the pilot hole.
The desirability of combining a drill, for making pilot holes, with a screwdriver, for putting screws in the pilot holes, has been long recognized. Applicant is aware of the following patents which disclose apparatus for accomplishing this purpose:
______________________________________ U.S. Pat. No. Issue Date Inventor Title ______________________________________ 274,042 Mar 13, 1883 Smith CONVERTIBLE SCREW DRIVER AND BORER 366,205 July 12, 1887 Cronk COMBINED SCREW DRIVER AND BRAD AWL 529,401 Nov 20, 1894 McCoy SPIRAL SCREW DRIVER AND DRILL 3,484,114 Sep 12, 1967 Rodin SCREW INSTALLING ATTACHMENT FOR POWER TOOLS 3,932,904 Jan 20, 1976 Nilsson COMBINATION TOOL 3,965,510 Jun 29, 1976 Ernst COMBINATION DRILLING AND WRENCHING TOOL 4,512,693 Apr 23, 1985 Swanson REVERSIBLE DRILL AND DRIVER TOOL HOLDER 4,796,319 Jan 10, 1989 Taft COMBINATION SCREW-TAPPING AND SCREW- DRIVING TOOL 5,129,118 Jul 14, 1992 Walmesley ACCESSORY TOOL APPARATUS FOR USE ON POWER DRILLS 5,191,666 Mar 9, 1993 Corbin DRILL ADAPTER ______________________________________
The patents to Rodin, Taft, Walmesley, and Corbin disclose combination tools for power tools (electric drills) wherein the chuck of the electric drill supports a drill bit and a screwdriver is supported in each instance by a sleeve that fits over the chuck of the electric drill.
The combination tools of Nilsson, Ernst, and Swanson each include a shank whose sole function is to be attached to the chuck of an electric drill to transmit torque from the electric drill to the combination tool. See the central stub axle 4 in Nillson; the mandrel 14 in Ernst; and the tang 19 in Swanson.
None of the combination tools used with electric drills in the prior art known to applicant have captured the simplicity and ease of operation that is found in the patents issued to Smith and Cronk more than one hundred years ago--before the invention of electric drills. Smith and Cronk put a hole "borer" or "brad awl" on one end of a strip of metal and a screwdriver on the other end of that strip. The strip of metal was held in a hollow handle with the desired end extending outwardly for use.
The apparatus invented by applicant carries the simplicity and ease of operation of Smith and Cronk forward for use with the convenience and labor saving advantages of electric drills.